The present invention relates to a method of manufacturing a semiconductor device such as a thin-film transistor or the like to be formed on an insulating substrate, and an apparatus for manufacturing this semiconductor device.
A technique for manufacturing a semiconductor device such as a thin-film transistor (hereinafter to be referred to as a TFT) or the like on an insulating substrate such as glass, quartz or others has been utilized in various kinds of fields such as for application to an active matrix type liquid crystal display unit and others, and attention has been focused on this technique.
In a conventional TFT, amorphous silicon (hereinafter to be referred to as a-Si:H) or the like is uses for an active layer and source and drain electrodes are disposed on this a-Si:H through an ohmic contact layer like n+a-Si:H or others. In recent years, an attempt has been made to use polycrystalline silicon (p-Si) for an active layer in order to have improved mobility to secure sufficient operation speed.
One example of a method of manufacturing this kind of thin-film transistor will be explained below.
For example, a thin film of an amorphous silicon is deposited on a transparent glass substrate to have a desired film thickness by plasma CVD (Chemical Vapor Deposition) method or the like, and this film layer is crystallized by annealing such as ELA (Excimer Laser Annealing) or the like, thereby to form a polycrystalline silicon (p-Si) thin film. Then, after pattering this p-Si thin film, a gate insulating film is deposited on this, and further, a metal film such as an Al alloy or the like is deposited.
A resist pattern is disposed on this metal film, and the metal film is patterned by RIE (Reactive Ion Etching) or the like based on the resist pattern, thereby to form gate electrodes. Then, after removing the resist by ashing, a dopant ion is doped into the p-Si thin film by using the gate electrodes as a mask so as to form source areas and drain areas.
Thereafter, the substrate is heated at 500xc2x0 C. to activate the doped ion. Then, an inter-layer insulating film is deposited on this, and contact holes are formed by wet etching the gate insulating film and the inter-layer insulating film on the source and drain areas respectively. Then, a drain electrode electrically connected to the drain area and a source electrode electrically connected to the source area are formed respectively to complete a thin-film transistor.
According to the above-described method of manufacturing a thin-film transistor, the respective etching-patterning process, the ion doping process and the activation process are carried out by individual processing units. Accordingly, it requires many expensive individual units and it also takes a long time, for manufacturing a semiconductor device represented by the thin-film transistor. Thus, it has been difficult to sufficiently lower the manufacturing cost.
It has also become clear that unfinished products are stagnated between a plurality of processing units, and this undesirable stagnant brings about adhesion of fine particles and adsorption of water in the atmosphere onto and into the surface of the elements area of the substrate, which causes a reduction in production yield.
The present invention has been contrived to solve the above-described technical problems, and its object is to provide a method and an apparatus for manufacturing a semiconductor device, capable of reducing the processing time and the number of expensive processing units required for the manufacturing of the semiconductor device.
Further, it is also an object of the invention to provide a method and an apparatus for manufacturing a semiconductor device, capable of reducing an undesirable stagnation of unfinished products between manufacturing processes, thereby achieving high productivity.
In order to achieve the above objects, according to one aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of:
forming a first thin film consisting of an amorphous silicon thin film on an insulating substrate; forming a second thin film on the first thin film; etching the second thin film to form a mask pattern; and doping an impurity ion into the first thin film through the mask pattern;
wherein the mask pattern forming process and the ion doping process are carried out continuously without exposing the insulating substrate to the atmosphere.
Further, according to another aspect of the invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of:
forming a first thin film consisting of an amorphous silicon thin film on an insulating substrate; forming a second thin film on the first thin film; etching the second thin film to form a mask pattern; and doping an impurity ion into the first thin film through the mask pattern;
wherein the mask pattern forming process and the ion doping process are carried out continuously without exposing the insulating substrate to the atmosphere.
Further, according to still another aspect of the invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of:
forming a first thin film consisting of an amorphous silicon film on an insulating substrate; forming a second thin film on the first thin film; forming a resist pattern on the second thin film;
forming a mask pattern by etching the second thin film based on the resist pattern; doping an impurity ion into the first thin film through the mask pattern; and removing the resist pattern after the mask pattern forming process or after the ion doping process,
wherein the mask pattern forming process, the ion doping process and the removing process are carried out continuously without exposing the insulating substrate to the atmosphere.
Further, according to still another aspect of the invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of:
forming a first thin film consisting of an amorphous silicon film on an insulating substrate; forming a second thin film on the first thin film; etching the second thin film to form a first mask pattern; forming a source area and a drain area by doping an impurity ion into the first thin film through the first mask pattern; forming a second mask pattern by side-etching the first mask pattern following the ion doping process; and forming an electric field relaxation area with lower impurity density than that of the source area and the drain area, by doping an impurity ion into the first thin film through the second mask pattern,
wherein the first and second mask pattern forming processes, the source and drain areas forming process, and the electric field relaxation area forming process are carried out continuously without exposing the insulating substrate to the atmosphere.
Further, according to still another aspect of the invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of:
forming a first thin film consisting of an amorphous silicon film on an insulating substrate; forming a second thin film on the first thin film; forming a mask pattern by etching the second thin film; and forming an ohmic contact area by doping an impurity ion into the first thin film through the mask pattern,
wherein the mask pattern forming process and the ion doping process are carried out continuously without exposing the insulating substrate to the atmosphere.
Further, according to still another aspect of the invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of:
forming a first thin film consisting of an amorphous silicon film on an insulating substrate; forming a second thin film on the first thin film; forming a resist pattern on the second thin film; forming a mask pattern by etching the second thin film based on the resist pattern; forming an ohmic contact area by implanting an impurity ion into the first thin film through the mask pattern; and removing the resist pattern after the mask pattern forming process or after the ion doping process,
wherein the mask pattern forming process, the ion doping process, and the removing process are carried out continuously without exposing the insulating substrate to the atmosphere.
According to the above-described method of manufacturing a semiconductor device, as the patterning process and the ion doping process are carried out continuously without exposing the insulating substrate to the atmosphere, it is possible to substantially reduce the manufacturing time. Particularly, it is possible to reduce the number of expensive processing units by carrying out those processes within the same chamber. Thus, investments in the processing units can be reduced substantially and a space occupied by each processing unit can also be reduced. Furthermore, as there is no unnecessary stagnation of unfinished products in the middle of the processes, it is possible to prevent the adhesion of fine particles and adsorption of water in the atmosphere onto and into the surface of the element area of the substrate. As a result, productivity can be improved as compared with the prior-art technique.
On the other hand, according to still another aspect of the invention, there is provided a manufacturing apparatus for manufacturing a semiconductor device, comprising: a processing chamber internally equipped with a susceptor for supporting a substrate to be processed; exhaust means connected to the processing chamber, for exhausting the processing chamber in vacuum; gas supply means connected to the processing chamber, for supplying a reaction gas to the processing chamber; a first power source for applying a predetermined voltage to the substrate to be processed; activating means including a second power source, for activating the reaction gas introduced into the processing chamber; and a control section for selectively carrying out one of an ion doping process for doping an ion into the substrate to be processed or an etching process, by controlling the first and second power sources and the reaction gas.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.